1. Field of Invention
The present invention relates to a mixed light source display. More particularly, the present invention relates to a dual mode liquid crystal display (LCD) that integrates a liquid crystal display device and a light-emitting diode (LED) display device together.
2. Description of Related Art
In recent years, reflective liquid crystal display that utilizes incoming light as a light source is widely popular because there is no need to provide back light. Without the need to generate back light, power consumption is low and the display panel can be slimmer and lighter.
A conventional reflective liquid crystal display device includes an upper substrate, a polarizer plate and a quarter wave plate over the upper substrate, a lower substrate, a reflective layer over the lower substrate and a liquid crystal layer between the upper and the lower substrate. Since external light source is used as a source of illumination, power consumption is typically low. However, one major defect is that the display has some difficulties in displaying dark background area.
On the other hand, a conventional light-emitting diode display device has an upper and a lower glass substrate. To eliminate as much reflection between various interfaces as possible and increase image contrast, a quarter wave plate and a polarizer plate are still attached to the upper glass substrate. In other words, the basic structure and the polarizer plate structure of the light-emitting diode display device is very similar to the reflective liquid crystal display device. Although most light-emitting diode display device consumes roughly ten times the electrical power of a reflective liquid crystal display device, one major advantages is that the light-emitting diode display device is unaffected by background light intensity.